Project Summary: The Pilot Core B will support one of the principle mechanisms by which the Boston Roybal Center for Active Lifestyle Interventions (RALI Boston) will address its overarching goal to develop and test behavior change strategies that increase physical activity and promote healthy aging, especially for persons at high risk for poor health outcomes. The Pilot Core will achieve this goal by supporting a group of innovative and scientifically rigorous clinical trials by pilot investigators who will enhance our knowledge base, develop novel research methodologies and tools, disseminate our results, and ultimately work collaboratively to develop the pilot data and experience necessary to conduct future full-scale translational interventions using clinical trials. The specific aims of the Core are: 1) to solicit, select, and support two to three of the most meritorious pilot studies submitted to us each year to develop and test novel multicomponent strategies to promote behavioral changes that advance the science and result in improved health and well-being for older people; 2) to oversee and support the progress of pilot investigators and their projects and provide resources to assure their success in testing the feasibility, acceptability and efficacy of behavioral interventions guided by the NIH Stage Model; 3) to apply the research findings from the pilot projects to design translational projects and work with investigators to seek additional funding to develop and test them at different phases of the NIH Stage Model; 4) to implement procedures to assure the scientific integrity, rigor and reproducibility of our research and the safety of human subjects. The Pilot Core Leaders (Drs. Margie Lachman, Lewis Lipsitz and Theresa Ellis) will work closely with the Management and Administrative Core to ensure the Center operates smoothly and fulfills its aims. Procedures are in place to solicit, review and support new pilot projects. The pilot projects will draw on the most promising recent evidence linking psychosocial, behavioral, cognitive, and neuroscientific factors to health and to explore mechanisms involved in motivation and behavior change. Two pilot studies are proposed for the initial period of this renewal application to examine the efficacy of enhancing both motivation and executive control, two processes that have shown promise in engendering increased physical activity in sedentary individuals. One pilot is a randomized controlled trial that will test the feasibility and effects of a 10- session transcranial direct current stimulation (tDCS) intervention targeting the left dorsolateral prefrontal cortex on adherence to a personalized physical activity goal in physically-inactive older adults without overt illness or disease. The second pilot will examine the effects of two psychosocial factors, positive messaging and self-affirmation, on motivation and engagement in physical activity and their maintenance over time, compared to a control group that receives only positive messaging. Results of these studies will be used to develop new interventions for testing in larger scale clinical trials. The pilot core will continue to oversee the development of novel pilot studies and the translation and dissemination of findings from the Center.